Detailed Product Description 1.flexible ventilation duct durable material made of Aluminium foil+PET+helix steel wire .2.Apply for low /medium / high pressure, use for air ventilation in each environment . 3.Round style, and easy to install oval or round connection . 4.Fireproofing,at high temperatures or in case of fire ,no toxic gas emitted .5.Easy to delivery .6.Our price is lowest , the ...